CVE-2026-114140: nbconvert: File write via path traversal in cell output filenames
Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.
Generated by VEDAS. Scores as of 2026-11-11 15:49 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.
What it is
The nbconvert tool, jupyter nbconvert, converts Jupyter notebooks to various other formats via Jinja templates. From 5.4.0 until 7.17.2, ExtractOutputPreprocessor in nbconvert/preprocessors/extractoutput.py joins the attacker-controlled cell output metadata filename to output_files_dir without limiting the result to the intended directory. When a victim converts a malicious notebook with the markdown, LaTeX, reStructuredText, or AsciiDoc exporter, path traversal in the output filename can write attacker-controlled output data to arbitrary locations accessible to the victim. Running the notebook cell again replaces the malicious output metadata, but merely converting the supplied notebook does not. This issue is fixed in version 7.17.2.
Description quoted from the CVE record (assigned by GitHub_M, published 2026-10-21).
Weakness: CWE-22: Improper Limitation of a Pathname to a Restricted Directory (‘Path Traversal’)
How it can be exploited
Exploitable over the network with low attack complexity only when specific conditions are present needing low privileges and a user must actively take an action. Impact: confidentiality high, integrity high, availability high. CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
CISA assessment (SSVC): CISA assesses that a public proof of concept exists. Automatable: no. Technical impact: total.
Public exploit evidence (Exploit Observer)
Exploit Observer has no public exploit code naming this CVE. Check Exploit Observer for anything new.
Live scores
- EPSS
- 0.005
low predicted chance of attack - VEDAS
- 0.971
strong exploit evidence - On CISA KEV
- Not listed
- Detection rule
- No public rule yet
Who is affected
| Product | Affected | Not affected |
|---|---|---|
| jupyter nbconvert | version >= 5.4.0, < 7.17.2 | Not stated |
Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.
How to fix it
No fixed version or vendor advisory is listed in the CVE record yet. Watch the vendor’s security page.
How to detect it
There is no open VEDAS detection rule for this bug yet. It is listed on the detection gaps page if CISA has confirmed attacks.
References
Other references
- https://github.com/jupyter/nbconvert/security/advisories/GHSA-pjvx-prjx-h659 (x_refsource_CONFIRM)
- https://github.com/jupyter/nbconvert/commit/ce4bd99aec31d81d759fa8eeb8643179392ec66f (x_refsource_MISC)
- https://github.com/jupyter/nbconvert/releases/tag/v7.17.2 (x_refsource_MISC)
Other databases
Where this comes from
This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS), Exploit Observer. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.
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